Lisp in Go (with float64 only)

This is a Lisp interpreter compatible with lisp-in-dart except for numeric types: all numbers are float64. So it is a light version in a sense. I wrote it two years ago (2016) in Go 1.6 and 1.7. It had been presented under the MIT License at http://www.oki-osk.jp/esc/golang/lisp4-en.html (broken link) until last spring (2017).

Just as lisp-in-dart, this is a Lisp-1 with TCO (tail call optimization) and partially hygienic macros but being a subset of Common Lisp in a loose meaning. It is easy to write a nontrivial script which runs both in this and in Common Lisp. Examples are found in lisp-in-dart/examples.

In addition, this has two concurrent constructs implemented with goroutine, future and force, which I reported in 2013 at http://www.oki-osk.jp/esc/golang/future.html (broken link). Thanks to pkelchte, you can get the reported implementation (that is another Lisp I wrote in Go) at pkelchte/tiny-lisp now.

See IMPLEMENTATION-NOTES.md for the implementation.

How to run

$ go build lisp.go
$ ./lisp
> (+ 5 6)
11
> *version*
(1.42 "go1.10.1 darwin/amd64" "Nukata Lisp Light")
> (exit 0)
$

The value of *version* will vary depending on the Go compiler. See lisp.go L682-L691.

You can give the lisp command a file name of your Lisp script. If you put a "-" after the file name, it will begin an interactive session after running the file.

$ cat fib.l
(defun fib (n)
  (if (<= n 1)
      n
    (+ (fib (- n 1))
       (fib (- n 2)))))
$ ./lisp fib.l -
> (fib 10)
55
> (fib 20)
6765
> (setq f (future (fib 30)))
#<future:0xc420078060:(<nil> . <nil>):&{0 0}>
> (force f)
832040
> (exit 0)
$ 

Here (fib 30) was evaluated concurrently in a new goroutine and the result was retrieved by force.

License

This is under the MIT License. See lisp.go L1743-L1763.